A train cover bridge of 100m length in 45 seconds at 60km/h
Answers
Answer:
Length of bridge = 100 m
=>Crosses in bridge in time = 45 sec
=> Speed of train is 60km/h
=> Let the length of train = x
:-Total distance = length of train + length of bridge = 100+ x
Convert km/h into m/sec
\rm \: 60 \times \dfrac{5}{18}ms {}^{ - 1} = \dfrac{50}{3} m {s}^{ - 1}60×
18
5
ms
−1
=
3
50
ms
−1
\therefore \rm \: formula∴formula
\rm \to\: speed \: = \dfrac{distance}{time}→speed=
time
distance
\to \: \rm \dfrac{50}{3} = \dfrac{100 + x}{45}→
3
50
=
45
100+x
\rm \to \: 50 = \dfrac{100 + x}{15}→50=
15
100+x
\rm \: \to \: 50 \times 15 = 100 + x→50×15=100+x
\rm \to \: 750 = 100 + x→750=100+x
\to\rm \: x \: = 650→x=650
So length of train = 650m
We have to find time time taken , so given
Speed = 50/3 m/s
Distance = 650 m
\begin{gathered} \rm \: \implies formula \\ \boxed{\rm \: speed = \frac{distance}{time \: } }\end{gathered}
⟹formula
speed=
time
distance
Put the value , we get
\rm \: \dfrac{50}{3} = \dfrac{650}{x}
3
50
=
x
650
\rm \: \dfrac{1}{3} = \dfrac{13}{x}
3
1
=
x
13
\rm \: x = 39x=39
so t = 39 sec
=> time taken by the train to cross a clock tower= 39 sec
Step-by-step explanation:
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